Inositol 1,4,5-trisphosphate and cyclic ADP-ribose mobilize Ca2+ in a protist, Euglena gracilis.
Inositol 1,4,5-trisphosphate (InsP3) and cyclic ADP-ribose (cADPR) released Ca2+ from microsome fraction prepared from Euglena gracilis in dose-dependent manners. Caffeine, which also induced Ca2+ release from the microsomes, caused desensitization of the Ca2+ response to cADPR, although the Ca2+ response to InsP3 was not affected by caffeine. Further, ruthenium red inhibited the Ca2+ release induced by cADPR, but not by InsP3. These results suggest that cADPR functions as an endogenous messenger to activate a caffeine-sensitive, Ca(2+)-release mechanism, whereas InsP3 induces Ca2+ release by a distinct mechanism in E. gracilis.
Masuda
W
W
Department of Applied Biological Chemistry, Osaka Prefecture University, Japan.
Takenaka
S
S
Tsuyama
S
S
Tokunaga
M
M
Yamaji
R
R
Inui
H
H
Miyatake
K
K
Nakano
Y
Y
D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D036563:Cyclic ADP-Ribose; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005056:Euglena gracilis; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D012430:Ruthenium Red / Q000494:pharmacology
D010726:Phosphodiesterase Inhibitors; D012430:Ruthenium Red; D036563:Cyclic ADP-Ribose; D000246:Adenosine Diphosphate Ribose; D002110:Caffeine; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium